1. Field of the Invention
The present invention relates to a gas turbine combustor.
2. Description of the Related Art
In known related art regarding recuperated gas turbines, as disclosed in, e.g., JP,A 9-329335 and JP,A 2001-107748, a fluid compressed by a compressor is extracted, and the extracted fluid is heated in a recuperator through heat exchange with gas-turbine exhaust gas and then injected into a combustor, whereby the amount of fuel charged into the combustor is reduced and thermal efficiency is increased.
For the purpose of coping with the combustor outlet temperature heated up to high temperatures, the above-cited JP,A 9-329335 and JP,A 2001-107748 disclose techniques in which a transition duct alone or both the transition duct and a combustor liner are cooled by a relatively low-temperature fluid before recuperation, the fluid is extracted from a combustor outer casing and then passed to the recuperator, and the extracted fluid is injected again to the combustor outer casing for use in combustion.
In this connection, the above-cited publications disclose means for cooling the combustor transition duct to cope with the combustor outlet temperature heated up to high temperatures, thereby increasing the thermal efficiency. The cooling means functions to cool the transition duct alone or both the transition duct and the combustor liner by the relatively low-temperature fluid before recuperation. Thereafter, the fluid is extracted from the combustor outer casing and passed to the recuperator, following which the extracted fluid is injected again to the combustor outer casing for use in combustion.